Water-permeable drum for the hydrodynamic needling of webs of textile materials, and method for the production of said drum

ABSTRACT

The invention relates to a previously known water-permeable drum for hydrodynamically needling webs of textile materials such as nonwovens, tissue, cloth, knitted fabrics, or similar in order to reinforce and structure said textile materials and/or refine the surface thereof. Said intrinsically stable drum is provided with apertures and a tubular sieve-type cloth or knitted fabric which is made of metal wires, is pulled across the outer circumference thereof, and is fixed to the face of the drum. In order to prevent creases from forming across the area of the sieve-type cloth when the drum is used according to the specifications, the sieve-type cloth or knitted fabric is provided with a coating that stabilizes the intersections of the wires. Said coating should be a galvanically applied coating, e.g. a nickel plating.

The invention relates to a water-permeable drum for the hydrodynamicneedling of textile materials such as nonwovens, tissue, cloth, knittedfabrics or similar in order to reinforce and structure said textilematerials and/or refine the surface thereof, consisting of anintrinsically stable drum provided with apertures and a tubularsieve-type cloth or knitted fabric which is made of wires.

Such drums are known in the field of flow-through drying from GBM 1 886883. The design is advantageous because the textile material to betreated does not lie on the perforated drum which would result innonuniform flow through the material web and marking of the drumperforation on the textile material. If, on the other hand, a coarsesieve-type woven fabric is preferably located first on the drum and thena finer fabric on which the textile material then comes to rest, thetreatment medium can treat the textile material uniformly over thesurface. For hydrodynamic needing it has also been considered that thecoarse sieve-type cloth, that is the under-covering, is replaced bystrips arranged closely adjacent to one another, for which purposereference is made to EP-A-O 841 424.

Practice has shown that creases form over the surface of the sieve-typecloth or knitted fabric. Creases form in the sieve-type cloth even whenthe sieve-type cloth consists of a diagonally woven or used tubularcloth which decreases in diameter under an axial tension produced duringassembly and thus comes to rest during assembly firmly and over theentire area on the supporting sieve drum or on the under-coating.Creases which are formed in practice, that is when the needling drum isused as the textile-material transporting drum, are especiallydisadvantageous. Nonuniform distortions which need to be avoided in anycase are then formed in the textile material as a result of thedistortions in the sieve-type cloth.

It is the object of the invention to develop a drum with sieve-typecloth or knitted fabric looped around said drum wherein this formationof creases is made impossible.

Starting from the drum of the type specified initially, the inventionconsists in the fact that the sieve-type cloth or knitted fabric has acoating that stabilizes the intersections of the wires. The sieve-typeover-covering consists of metal wires which are interwoven or knittedtogether. Of necessity there is always the possibility of movement ofthe metal wires at the intersections of this over-covering. This isprevented by the coating. Thus, no more creases can form over thesurface of the drum.

It is especially advantageous if, as is known, the sieve-type cloth orknitted fabric is manufactured as a hose with a diagonal wire structure,it is then pulled over the sieve drum and brought to rest underlongitudinal tension so that it abuts against the jacket of the sievedrum over the entire area, or better, on a previously appliedunder-covering such as coarser sieve-type cloth. The over-coveringshould be joined to the two faces of the drum, which is usually effectedby soldering. The over-covering should then be coated, and specificallywith a coating that stabilizes the sieve-type cloth or knitted fabric atthe intersections of the wires.

In a simpler production process it is also possible to carry out thecoating before assembling the over-covering. The only important thingwith the desired drum is that the over-covering abuts against the sievedrum as firmly as possible over its entire area and the mobility of thewires is additionally eliminated. This is produced by the proposedcoating. which can be provided by plastic or by a galvanically producedmetal coating, for example, by nickel plating.

A drum of the type according to the invention and the possibleproduction process of the finally coated drum with over-covering isshown as an example in the drawings. In the figures:

FIG. 1 is a perspective view of a perforated sieve drum with asieve-type cloth pulled on under tension, which according to

FIG. 2 is completely dipped in a bath to produce a galvanically producedover-covering both over the ready-assembled sieve-type cloth and alsoover the drum, the same is disclosed by

FIG. 3 in the case of a perforated drum with a coarse sieve-type clothapplied previously to the drum as an under-covering for the additionallyfiner sieve-type cloth. This assembled drum, according to

FIG. 4 is dipped in the bath for galvanic coating with nickel.

FIG. 5 shows the production process for a sieve drum with coveredsieve-type cloth comprising partial steps a)-c) wherein the hose ofsieve-type cloth is nickel-plated, for example, without axial tensionand is then pulled over the drum and is soldered, clamped or similarlyattached; then

FIG. 6 shows the production process for a sieve drum with coveredsieve-type cloth comprising partial steps a)-c) wherein the hose ofsieve-type cloth is nickel-plated, for example, with axial tension butbefore assembly with the sieve drum and is then pulled over the drum andis soldered, clamped or similarly attached to the drum under axialtension, and then

FIG. 7 shows the production process for a sieve drum with coveredsieve-type cloth comprising partial steps a)-b) wherein the initiallyuntreated hose of sieve-type cloth having a diagonal structure is pulledover the sieve drum, then set under longitudinal tension and soldered,clamped or otherwise attached to the faces of the sieve drum. Only thenis the assembled drum dipped in the bath to nickel plate all the parts.

FIG. 8 further shows an enlarged view of a cross-section through thecoated sieve-type cloth or knitted fabric and

FIG. 9 shows the coated sieve-type cloth in a view similar to FIG. 8 butsaid cloth was coated after mounting on the sieve drum so that as aresult of the coating, a connection of the sieve-type cloth with thecircumferential surface of the sieve drum also exists.

In the afore-mentioned EP-A-O 841 424 in FIG. 1 a device is describedwhere the textile material to acted upon by the water jets is guidedbetween the endless sieves moving conically towards one another and thusthe water jets initially pass through a sieve to bring about theneedling. Normally the textile material lies directly on the drum as isshown in FIG. 2 in EP-A-1 001 064 and the nozzle beam or beams with theemerging water jets are directly associated with the textile material.The water-permeable drum according to the design according to theinvention is applicable to both cases of application.

With its circumferential surface, the perforated sieve is drum 1 (theperforations 2 are shown in FIG. 2) serves as the element which bearsthe textile material and transports it forwards. The perforations in thecircumferential surface are used for radially directed removal of thewater of the impinging water jets, for which purpose the interior of thedrum is under induced draft. In order that this takes place uniformlyover the surface of the textile material, a sieve-type cloth 3 is pulledover the drum 1, as shown in FIGS. 1 and 2, the cloth can have a finerstructure and be soldered to the faces of the drum 1 under tension 4.The sieve-type cloth or knitted fabric usually consists of a hose havinga diagonal structure so that the hose is reduced in diameter under thelongitudinal tension produced during assembly and thus comes to rest onthe drum 1 with its entire area.

Since the wire structure of the sieve-type cloth or knitted fabric 3also remains movable when the hose is under tension, the ready-assembleddrum 1+3 according to FIG. 2 is dipped in a bath 5 and is coated withnickel using the galvanic method. The coating can also be accomplisheddifferently e.g., by zinc plating or using a plastic material which canbe sprayed on. As a result, not only the wire structure of thesieve-type cloth 3 is fixed permanently but also a connection of thesieve cloth 3 with the drum 1 is produced over the entire area.

FIGS. 3 and 4 disclose the same except that a finer-structure tubularsieve-type cloth 6 is pulled over the coarser sieve-type cloth 3 and isalso brought to rest firmly on the drum 1+3 under tension 4 and issoldered to the faces of the drum. The coating is only then carried outaccording to FIG. 4.

A sieve drum with sieve-type cloth or knitted fabric looped around it,which is stabilized by a coating at the intersections of the wires, canbe produced in many ways. According to FIG. 5, a hose 6′ is suitablymade of a desired cloth or knitted fabric in a simple fashion accordingto a), then dipped in a galvanizing bath 5 according to b) and coated,and is then pushed over a relevant drum 1′ and soldered, clamped orotherwise attached to the face of the drum under tension 4″ (not shown).

It is better if, as is shown in FIG. 6, the tubular sieve-type cloth 6′is gripped at the side by an auxiliary structure 7, 8 and is stretchedto the correct dimension according to the arrow 4′. Then, as in FIG. 5b, the sieve-type cloth 6′, again without the drum but in the tensionedstate, is coated in the bath 5 and then pushed over the sieve drum 1′according to c) and soldered, clamped or otherwise attached to the facesof the drum under tension 4″ (not shown).

The best solution is disclosed in FIG. 7. According to FIG. 7 a, thetubular sieve-type cloth 6″ having a diagonal structure is pushed overthe sieve drum 1, gripped at the faces by means of the auxiliarystructure and soldered or otherwise fixed to the faces of the drum 1under tension 4″. This corresponds to the diagram in FIGS. 1 or 3. Thefinally assembled drum 1 with the sieve-type cloth 6″ resting thereonover the entire area and soldered thereto is then inserted in thedipping bath for coating as shown in FIG. 7 b in order to obtain thedesired drum with the coated sieve-type cloth 6″ positioned firmlythereon as a result of the coating as shown in FIG. 9.

The stabilizing coating of the sieve-type cloth or knitted fabric isdeduced from FIGS. 8 and 9. By applying the coating means to the wiregauze 6, 6″, 6″, a connection 10 of the superimposed wires 9 is achievedin any case at all intersections of the wires 9, which resembles awelding of the wires 9. The basically loose wire gauze is thusstabilized over the area. The diagram in FIG. 8 corresponds to themethod of producing the drum according to FIG. 5 and 6. According toFIG. 9, not only the wire cloth is stabilized but this is also connectedto the underlayer by the coating 10′. The underlayer can be the sievedrum 1 according to FIG. 1 or the under-covering 3 according to FIG. 3which is likewise connected to the sieve drum 1 by the coating 10′ afterthe production process according to FIG. 7.

1-15. (canceled)
 16. Water-permeable drum for the hydrodynamic needling of textile materials such as nonwovens, tissue, cloth, knitted fabrics or similar in order to reinforce and structure said textile materials and/or refine the surface thereof, consisting of an intrinsically stable drum provided with apertures and a tubular sieve-type cloth or knitted fabric which is made of wires, is pulled across the outer circumference thereof, and is fixed to the face of the drum, characterized in that said sieve-type cloth or knitted fabric (3, 6, 6′, 6″) has a coating (10) that stabilizes the intersections of the wires (9).
 17. The drum according to claim 16, characterized in that said drum (1) is provided with an under-covering (3) which increases the distance between the surface of the sieve drum and sieve-type cloth or knitted fabric (3, 6, 6′, 6″) and at least the sieve-type cloth or knitted fabric has a coating (10) that stabilizes the intersections of said wires (9).
 18. The drum according to claim 16, characterized in that the sieve-type over-covering (3, 6) on the sieve drum (1) is applied to said sieve drum (1) under tension (4″), is fixed to the faces of said drum and abuts closely against the surface of said sieve drum over its entire area, and has a coating (10) that stabilizes the intersections of said wires (9) (FIGS. 6 and 7).
 19. The drum according to claim 16, characterized in that the sieve-type over-covering (6″) on the sieve drum (1) is applied to said sieve drum (1) under tension (4″) and is fixed to the faces of said drum, has a coating (10) that stabilizes the intersections of said wires (9) and is additionally connected to the contact surface such as the surface of the sieve drum by the coating (10′).
 20. The drum according to claim 16, characterized in that the coating is made of plastic.
 21. The drum according to claim 16, characterized in that the coating consists of metal.
 22. The drum according to claim 21, characterized in that the coating is produced galvanically.
 23. The drum according to claim 16, characterized in that the coating is produced by dipping treatment.
 24. The drum according to claim 21, characterized in that the coating consists of nickel.
 25. The drum according to claim 21, characterized in that the coating consists of zinc.
 26. A method for manufacturing a water-permeable drum comprising a sieve-type cloth or knitted fabric which is looped around said drum and is fixed to the faces of said drum, characterized in that the web-type labile sieve-type cloth or knitted fabric is provided with a coating which stabilizes the intersections of the wires, it is then cut transversely, and the section thus produced is joined to form a tube and said tube of now stable sieve-type cloth or knitted fabric is pulled over the drum and is fixed to the faces thereof.
 27. A method for manufacturing a water-permeable drum comprising a sieve-type cloth or knitted fabric which is looped around said drum and is fixed to the faces of said drum, characterized in that a hose is made of a labile sieve-type cloth or knitted fabric, said hose is formed into an exactly-fitting tube and is brought under tension longitudinally, said tube is provided with a coating which stabilizes the intersections of the wires and said stable tube is pulled over the sieve drum and is connected to the faces of said drum.
 28. The method defined in claim 27, further comprising the steps of pulling a hose of a labile sieve-type cloth or knitted fabric over the drum, fixing it to the faces of said drum under longitudinal tension and thereby bringing it in contact with the surface of the drum over the entire area and then at least the sieve-type cloth or fabric is provided with a stabilizing coating.
 29. The method defined in claim 27, further comprising the step of pulling a hose made of a labile sieve-type cloth or knitted fabric and is covered with an under-covering which increases the distance over the drum, and is thereby bringing it in contact with the surface of the under-covering over the entire area and then providing the sieve-type cloth or knitted fabric and also the under-covering with a stabilizing coating.
 30. The method defined in claim 27, further comprising the steps of pulling a hose made of a labile sieve-type cloth or knitted fabric and over the drum and fixing said hose to the faces of said drum under longitudinal tension and thereby bringing it in contact optionally with the surface of the under-covering over the entire area and then providing the sieve-type cloth or knitted fabric, optionally the under-covering and also the sieve drum with a coating, whereby the sieve-type cloth or fabric is connected over the entire area to the sieve drum or the under-covering applied thereto by means of the coating. 